Calculate the percentage of radioactivity remaining after 289 years if it's half-life is 28 years

Explain why scientists use shared characteristics to make cladograms.

The atomic number, or number, is the described as the number of in the nucleus of an chemical element.

Observation and experimentation have led many scientists to accept a theory about the origin of the universe. this theory is called the big bang theory. scientific evidence collected and observed by scientists around the world suggests that the universe is ever expanding from a hot and dense initial state. what makes this a scientific theory? (2 points)